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161.
Compost impacts on dissolved organic carbon and available nitrogen and phosphorus in turfgrass soil 总被引:1,自引:0,他引:1
Wright AL Provin TL Hons FM Zuberer DA White RH 《Waste management (New York, N.Y.)》2008,28(6):1057-1063
Compost application to turfgrass soils may increase dissolved organic C (DOC) levels which affects nutrient dynamics in soil. The objectives of this study were to investigate the influence of compost source and application rate on soil organic C (SOC), DOC, NO(3), and available P during 29 months after a one-time application to St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] turf. Compost sources had variable composition, yet resulted in few differences in SOC, DOC, and NO(3) after applied to soil. Available NO(3) rapidly decreased after compost application and was unaffected by compost source and application rate. Available P increased after compost application and exhibited cyclical seasonal patterns related to DOC. Compost application decreased soil pH relative to unamended soil, but pH increased during the course of the study due to irrigation with sodic water. Increasing the compost application rate increased SOC by 3 months, and levels remained fairly stable to 29 months. In contrast, DOC continued to increase from 3 to 29 months after application, suggesting that compost mineralization and growth of St. Augustinegrass contributed to seasonal dynamics. Dissolved organic C was 75%, 78%, and 101% greater 29 months after application of 0, 80, and 160 Mg compostha(-1), respectively, than before application. Impacts of composts on soil properties indicated that most significant effects occurred within a few months of application. Seasonal variability of SOC, DOC, and available P was likely related to St. Augustinegrass growth stages as well as precipitation, as declines occurred after precipitation events. 相似文献
162.
Richards CE Munster CL Vietor DM Arnold JG White R 《Journal of environmental management》2008,86(1):229-245
The disposal of manure on agricultural land has caused water quality concerns in many rural watersheds, sometimes requiring state environmental agencies to conduct total maximum daily load (TMDL) assessments of stream nutrients, such as nitrogen (N) and phosphorus (P). A best management practice (BMP) has been developed in response to a TMDL that mandates a 50% reduction of annual P load to the North Bosque River (NBR) in central Texas. This BMP exports composted dairy manure P through turfgrass sod from the NBR watershed to urban watersheds. The manure-grown sod releases P slowly and would not require additional P fertilizer for up to 20 years in the receiving watershed. This would eliminate P application to the sod and improve the water quality of urban streams. The soil and water assessment tool (SWAT) was used to model a typical suburban watershed that would receive the sod grown with composted dairy manure to assess water quality changes due to this BMP. The SWAT model was calibrated to simulate historical flow and estimated sediment and nutrient loading to Mary's Creek near Fort Worth, Texas. The total P stream loading to Mary's Creek was lower when manure-grown sod was transplanted instead of sod grown with inorganic fertilizers. Flow, sediment and total N yield were the same for both cases at the watershed outlet. The SWAT simulations indicated that the turfgrass BMP can be used effectively to import manure P into an urban watershed and reduce in-stream P levels when compared to sod grown with inorganic fertilizers. 相似文献
163.
D.M. White P. Prokein M.K. Chambers M.R. Lilly H. Toniolo 《Journal of the American Water Resources Association》2008,44(2):276-284
Abstract: Water resources are limited in many areas of the North Slope, Alaska, particularly during winter. Water is used by the oil industry for ice road construction and maintenance, drilling and facility operations, and potable water supplies. The coastal plain between Teshekpuk Lake, in the National Petroleum Reserve‐Alaska (NPR‐A) and the Colville River has numerous shallow lakes, but further south in the northern foothills of the Brooks Range, and east to the Canning River, lakes are fewer. While many oil and gas lease sales have been conducted, or are proposed, access to the leases may be limited because of the lack of available water for ice road construction. Ice roads are the main means by which exploration is conducted in the Arctic, putting a stress on freshwater bodies that do not freeze to the lakebed in winter. Lakes that do not freeze to the lakebed also serve as overwintering habitat for fish. The purpose of this paper is to report on the potential distribution of water bodies that may provide overwinter water in selected areas from Teshekpuk Lake to the Canning River. The project used synthetic aperture radar (SAR) imagery to search for the presence of water in lakes in March 2006. In the Kuparuk and Canning SAR images, 52 and 61% of lakes were frozen to their beds by March 2006, accounting for 49 and 57% of the lake area in these study regions. Conversely, only 2% of the lakes in the Teshekpuk region were frozen to the bottom by March 2006. Unfrozen water was more available because of deeper and more numerous lakes in the Teshekpuk Lake region (west) than in the Canning River area (east). While only specific SAR tiles were analyzed herein, the method will be a useful tool for land managers who seek to evaluate the potential for ice road construction across the Arctic. 相似文献
164.
Uranium removal from groundwater via in situ biostimulation: Field-scale modeling of transport and biological processes 总被引:1,自引:0,他引:1
Yabusaki SB Fang Y Long PE Resch CT Peacock AD Komlos J Jaffe PR Morrison SJ Dayvault RD White DC Anderson RT 《Journal of contaminant hydrology》2007,93(1-4):216-235
During 2002 and 2003, bioremediation experiments in the unconfined aquifer of the Old Rifle UMTRA field site in western Colorado provided evidence for the immobilization of hexavalent uranium in groundwater by iron-reducing Geobacter sp. stimulated by acetate amendment. As the bioavailable Fe(III) terminal electron acceptor was depleted in the zone just downgradient of the acetate injection gallery, sulfate-reducing organisms came to dominate the microbial community. In the present study, we use multicomponent reactive transport modeling to analyze data from the 2002 field experiment to identify the dominant transport and biological processes controlling uranium mobility during biostimulation, and determine field-scale parameters for these modeled processes. The coupled process simulation approach was able to establish a quantitative characterization of the principal flow, transport, and reaction processes based on the 2002 field experiment, that could be applied without modification to describe the 2003 field experiment. Insights gained from this analysis include field-scale estimates of the bioavailable Fe(III) mineral threshold for the onset of sulfate reduction, and rates for the Fe(III), U(VI), and sulfate terminal electron accepting processes. 相似文献
165.
Epperson D Lev-On M Taback H Siegell J Ritter K 《Journal of the Air & Waste Management Association (1995)》2007,57(9):1050-1060
Controlling fugitive emissions from leaks in petrochemical industry process equipment now requires periodic monitoring of valves, flanges, pumps etc., typically on a quarterly basis. Previous studies have shown that over 90% of the reducible emissions come from approximately 0.1% of the components, i.e. the large leakers. A new, and more cost-effective approach for controlling these large leakers would entail more frequent monitoring of process equipment, allowing for the detection and repair of the highly leaking components that contribute the most to emissions. This approach has been called "Smart LDAR." New optical imaging instruments, which significantly reduce monitoring costs, are now available to implement such an alternative work practice. This work describes the determination of the leak detection sensitivity (equivalency threshold) that an optical imaging instrument must achieve to ensure that it will provide at least the equivalent emission control of the current leak detection and repair practice. Equivalency thresholds were developed for various monitoring intervals. The U.S. Environment Protection Agency's Monte Carlo simulation approach was used to perform the analysis and to demonstrate that optical imaging, which is capable of identifying all of the largest leakers, can provide better control of fugitive emissions. 相似文献
166.
167.
Runoff from two similar drainage areas in the Piedmont physiographic region of North Carolina was monitored simultaneously for 5.6 years. One of the drainage areas was developed as part of a large residential subdivision, while the other remained in woods and agricultural fields. Runoff volume was 68% greater for the developed compared with the undeveloped area, and baseflow as a percentage of overall discharge was approximately 0% compared with 25% for the undeveloped area. Overall annual export of sediment was 95% greater for the developed area, while export of nitrogen and phosphorus forms was 66 to 88% greater for the developed area. These results document the significant increases in runoff, sediment, and nutrient export associated with residential development. 相似文献
168.
Why do people get involved in the creation of new ventures? Prior research suggests entrepreneurial behavior has multiple causes. Nurture explanations; often couched in terms of sociological theories like social learning have been popular. Aspects of nascent entrepreneurs' social contexts, notably their family business background, have been associated with new venture creation. But nature also appears to play a role. Other research has linked heritable biological factors, including testosterone, with the career choice to launch a new venture. This study presents theory and evidence linking the combination of both sociological and biological factors with new venture creation: a biosocial model of entrepreneurship. Empirical results indicate new venture creation is more likely among those individuals having a higher testosterone level in combination with a family business background. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
169.
Guidance for the performance evaluation of three-dimensional air quality modeling systems for particulate matter and visibility 总被引:1,自引:0,他引:1
Seigneur C Pun B Pai P Louis JF Solomon P Emery C Morris R Zahniser M Worsnop D Koutrakis P White W Tombach I 《Journal of the Air & Waste Management Association (1995)》2000,50(4):588-599
Guidance for the performance evaluation of three-dimensional air quality modeling systems for particulate matter and visibility is presented. Four levels are considered: operational, diagnostic, mechanistic, and probabilistic evaluations. First, a comprehensive model evaluation should be conducted in at least two distinct geographical locations and for several meteorological episodes. Next, streamlined evaluations can be conducted for other similar applications if the comprehensive evaluation is deemed satisfactory. In all cases, the operational evaluation alone is insufficient, and some diagnostic evaluation must always be carried out. Recommendations are provided for designing field measurement programs that can provide the data needed for such model performance evaluations. 相似文献
170.
Sensitivity of marine fishes to toxins from the red-tide dinoflagellate Gonyaulax excavata and implications for fish kills 总被引:2,自引:0,他引:2
A. W. White 《Marine Biology》1981,65(3):255-260
Marine fishes (Atlantic herring, American pollock, winter flounder, Atlantic salmon, and cod) were dosed orally and intraperitoneally (i.p.) with paralytic shellfish toxins extracted from Bay of Fundy Gonyaulax excavata (tamarensis) cells. The toxins are lethal to these fishes in low oral doses, and in extremely low i.p. doses. Symptoms are the same among these fishes, both for oral and i.p. administrations, including loss of equilibrium within 5 to 15 min, followed by immobilization and shallow, arrhythmic breathing. Death generally occurs within 20 to 60 min of toxin administration. Dose responses are also similar among these fishes. Oral LD50 values are 400 to 750 g saxitoxin (STX) equivalent kg-1 body weight. Intraperitoneal LD50 values are 4 to 12 g STX equivalent kg-1. Toxins are undetectable in fish muscle tissue following lethal oral doses. The similarity of symptoms and dose responses suggest that fish as a group are sensitive to G. excavata toxins. Results, in combination with reports implicating these toxins in herring, sand lance, and menhaden kills, show the plausibility that the nearly worldwide blooms and red tides of G. excavata and its relatives may cause kills of a variety of fishes. 相似文献